An investigation by The Washington Post has revealed that America's intelligence system has grown so large since the September 11 attacks, that determining its effectiveness is "impossible".

Buildings have been cropping up across the country to house new government workers and contractors, yet the newspaper says the sprawling network is so massive and so secretive that nobody knows how much it costs, or how many agencies are doing the same work.

Al Jazeera's Rosiland Jordan reports.

Source: Al Jazeera